The present invention relates to a magnetic disk apparatus, and is specifically suited to a magnetic disk apparatus provided with a flying-amount adjustment slider having the function of adjusting a distance between a magnetic disk and a magnetic head.
Magnetic disk apparatuses comprise a rotating magnetic disk and a magnetic head slider mounting thereon a recording and reproducing element and supported and positioned radially by a load beam, the magnetic head slider running relatively on the magnetic disk to read and write magnetic information recorded on the magnetic disk. The magnetic head slider flies as an air lubricated bearing due to the wedge film effect of air, so that the magnetic disk and the magnetic head slider do not come into direct solid contact with each other. In order to realize making a magnetic disk apparatus high in recording density and to thereby realize making the apparatus large in capacity, or small in size, it is effective to decrease a distance between a magnetic head slider and a magnetic disk, that is, a slider flying amount to increase a track recording density.
Conventionally, in designing a slider flying amount, an individual difference in flying amount due to dispersion in working and assembly, a difference in flying amount due to ambient, atmospheric pressure in use, a difference in flying amount due to ambient temperature in use, a difference in flying amount due to recording/reproducing, and a difference in flying amount due to a radial position (peripheral speed) are beforehand estimated at the time of designing, and a margin in flying amount is provided so as to eliminate contact between a magnetic head slider and a magnetic disk even under most severe conditions. As such, reliability in magnetic disk apparatuses is ensured. Here, when it is possible to realize a magnetic disk apparatus provided with a magnetic head slider having the function of adjusting a flying amount every individual head, or according to an environment in use, it is possible to reduce the margin to decrease a recording and reproducing element in flying amount while preventing contact between a magnetic head slider and a magnetic disk.
JP-A-5-20635 (Patent Document 1) shows a conventional magnetic disk apparatus provided with a magnetic head slider having the function of adjusting a flying amount. With the magnetic disk apparatus in Patent Document 1, a heating device composed of a thin film resistor is provided in the neighborhood of a recording and reproducing element to heat a part of the magnetic head slider at need to cause thermal expansion thereof, thereby causing the recording and reproducing element portion to project to adjust a flying amount of the recording and reproducing element.
Also, JP-A-2003-297029 (Patent Document 2) shows a conventional magnetic disk apparatus provided with a magnetic head slider having the function of adjusting a flying amount. With the magnetic disk apparatus in Patent Document 2, a temperature sensor, a heating element, and a Peltier element are provided in the neighborhood of a recording and reproducing element, and the recording and reproducing element is maintained constant in temperature by a control circuit to enable maintaining a flying amount of the recording and reproducing element constant.